1. Field of the Invention
The present invention relates to a communication control system and method, a communication system, and a recording medium. More particularly, this invention is concerned with a communication control system and method for dynamically managing connection or disconnection of equipment within a system, a communication system, and a recording medium.
2. Description of the Related Art
FIG. 1 shows an example of the configuration of a system for transferring data placed on a fast serial bus conformable to the standard 1394 stipulated by the Institute of Electrical and Electronics Engineers (IEEE) over an asynchronous transfer mode (ATM) network. A video camera 1 is connected to a bridge 3-1 over an IEEE 1394 bus 2-1. Likewise, a monitor 4 is connected to a bridge 3-2 over an IEEE 1394 bus 2-2. The bridge 3-1 and bridge 3-2 are interconnected with an ATM switch 5 between them. For connecting the bridges 3-1 and 3-2 to the ATM switch 5, for example, an optical fiber is used.
Hereinafter, the IEEE 1394 buses 2-1 and 2-2 shall be generically referred to as an IEEE 1394 bus 2 unless they are required to be separated from each other. The same applies to the other components.
In the system shown in FIG. 1, an image produced by the video camera 1 is transmitted to the monitor 4 and then reproduced. At this time, the video camera 1 outputs image data to the bridge 3-1 at an isochronous channel 63. The bridge 3-1 is designed (initialized) so that channel numbers (0 to 63) will be associated with virtual channel identifiers (VCIS) or virtual path identifiers (VPI), which are employed in ATM communication, on a one-to-one basis. Herein, the bridge 3-1 is pre-set so that when data is transmitted at the channel 63, the bridge 3-1 starts transmitting the data in the ATM using an inherent virtual channel of an associated VCI or an inherent virtual path of an associated VPI. An ATM switch 5 selects the bridge 3-2 as a destination specified with the VCI or VPI, and transfers the data to the bridge 3-2.
When a connection has been established between the bridges 3-1 and 3-2, the connection is used to transfer image data. The bridge 3-2 converts received image data into data of a form acceptable by the monitor 4, and transfers the resultant image data to the monitor 4 over the IEEE 1394 bus 2-2.
As mentioned above, when the IEEE 1394 bus and ATM network is employed in a system, the permanent virtual connection (PVC) mode is adopted. According to the PVC mode, paths are determined relative to all remote terminals on a communication network, and a local terminal communicates with fixed remote terminals while being connected thereto all the time.
Equipment to be connected to other equipment over the IEEE 1394 bus, such as, the aforesaid video camera 1 and monitor 4 has an AV register incorporated therein. By changing values to be set in the AV register, isochronous channels at which data is transmitted or received can be switched. What is referred to as the AV register has a structure like the one shown in FIG. 2.
FIG. 2A to FIG. 2D show the structures of an output master plug register (oMPR), an output plug control register (oPCR), an input master plug register (iMPR), and an input plug control register (iPCR) constituting the AV register. FIG. 2A shows the structure of the OPCR, FIG. 2B shows the structure of the OPCR, FIG. 2C shows the structure of the iMPR, and FIG. 2D shows the structure of the iPCR. A code indicating a maximum transmission rate at which isochronous data transmissible or receivable by the equipment is transmitted is specified in a data rate capability field of the OMPR or iMPR to which two most-significant bits are assigned. A channel number used to broadcast data is specified in a broadcast channel base field of the oMPR.
A value representing the number of output plugs included in the equipment, that is, the number of oPCRs included therein is specified in a number-of-output plugs field of the OMPR to which five least-significant bits are assigned. A value representing the number of input plugs included in the equipment, that is, the number of iPCRs included therein is specified in a number-of-input plugs field of the iMPR to which five least-significant bits are assigned. A non-persistent extension field and a persistent extension field are defined for future functional expansion.
The used state of a plug is specified in an online field of the OPCR or iPCR. Specifically, when a bit assigned to the online field is 1, the plug is online. When the bit is 0, the plug is offline. A value specified in a broadcast connection counter of the OPCR or iPCR indicates whether a broadcast connection is present (1) or absent (0). A value specified in a point-to-point connection counter of the OPCR or iPCR that is 6 bits wide indicates the number of point-to-point connections accommodated by the plug.
A value specified in a channel number field of the OPCR or iPCR that is 6 bits wide indicates a number of an isochronous channel assigned to data that can be treated by the plug. A value specified in a data rate field of the OPCR that is 2 bits wide indicates an actual transmission rate adopted for transmission of a packet of isochronous data output through the plug. A code specified in an overhead identity (ID) field of the OPCR that is 4 bits wide indicates a bandwidth assigned to an overhead that is appended for isochronous communication. A value specified in a payload field of the OPCR that is 10 bits wide indicates a maximum value of data contained in an isochronous packet that can be treated by the plug.
A case where the video camera 1 and monitor 4 -transfer data on a point-to-point basis has been described so far. As shown in FIG. 3, a plurality of pieces of equipment may be interconnected over an IEEE 1394 bus subordinately to the bridge 3, and multiple pieces of equipment may transfer data to or from multiple pieces thereof. This multi-points-to-multi-points communication will be described below. According to an example of a system configuration shown in FIG. 3, four video cameras 1-1 to 1-4 are connected to the bridge 3-1 over an IEEE 1394 bus (not shown), and four monitors 4-1 to 4-4 are connected to the bridge 3-2 over an IEEE 1394 bus.
In the system-configuration shown in FIG. 3, a connection has already been established between the video camera 1-1 and monitor 4-1, and image data is transferred at the isochronous channel 63. Furthermore, when image data is transmitted from the video camera 1-2 to the monitor 4-2, the video camera 1-2 sets an isochronous channel. At this time, the same isochronous channel as that already used will not be set. For example, an isochronous channel 62 is set.
A connection is established between the bridge 3-1 and bridge 3-2, and data transfer is started. The PVC mode is adopted as a communication mode. A VCI or VPI to be associated with the isochronous channel 62 is determined in advance. The bridge 3-2 determines an isochronous channel, at which received image data is transmitted, according to the VCI or VPI, and sets an AV plug. The bridge 3-2 selects, similarly to the bridge 3-1, an isochronous channel (for example, isochronous channel 62) that is not the same as an already used isochronous channel, converts the received data into data having the selected isochronous channel 62, and transmits the resultant data. The monitor 4-2 reproduces input image data.
As mentioned above, an isochronous channel is set so that it will not be the same as an already used one. Multi-points-to-multi-points communication is thus achieved. However, equipment interconnected over an IEEE 1394 bus (within a system) may include equipment that does not have the ability to set an isochronous channel. Moreover, the bridge 3 itself may not have the ability to switch isochronous channels. The present applicant has proposed in Japanese Patent Application No. 10-149538 and Patent Cooperation Treaty No. JP99/02864 a method of setting an isochronous channel using a separate personal computer or the like.
However, a personal computer or the like must be installed separately and used to set an isochronous channel. Otherwise, the aforesaid processing is not carried out. In other words, it is impossible to transfer different data on a point-to-point basis during multi-points-to-multi-points communication. Moreover, even when point-to-multi-points communication is intended, image data output from the video camera 1-1 is transmitted to all the monitors 4-1 to 4-4 at the same time. This is because different isochronous channels cannot be selected as mentioned above. In short, since data is transmitted at one isochronous channel, the same data cannot help being transmitted to all pieces of equipment connected to one bridge.
A case where a plurality of bridges is, as shown in FIG. 4, connected to one ATM switch 5 will be discussed below. For multicasting images produced by a video camera 1-1 to monitors 4-1 to 4-3 connected to bridges 3-2 to 3-4, all paths must be pre-set in the ATM switch 5. Pre-setting the paths is time-consuming. For example, when point-to-point communication is adopted instead of multicasting, if all paths leading to 70 pieces of equipment are set in the ATM switch, 2415 paths (=70xc3x9769/2) must be set. If paths were set in consideration of multicasting alike, the setting would be quite time-consuming.
When the PVC mode is adopted, if the total of pieces of equipment is modified because remote equipment is added or excluded, the setting of paths must also be modified.
The present invention intends to break through the foregoing situation. An object of the present invention is to construct a user-friendly system. Specifically, the switched virtual connection (SVC) mode is adopted so that different data items can be transferred through respective communications even during multi-points-to-multi-points communication. Moreover, equipment accommodated by the system can be utilized effectively.
According to the first aspect of the present invention, a communication control system includes a retrieving means and an output means. The retrieving means retrieves bridges, to which two pieces of equipment out of a plurality of pieces of equipment having received an instruction of connection or disconnection are connected, from a database containing predetermined information. The output means outputs a command, which enables execution of the instruction, to at least one of the bridges retrieved by the retrieving means.
An updating means may also be included for updating the information contained in the database according to information of new connection or disconnection sent from a bridge.
The information contained in the database may be at least one of identification names with which bridges are identified, node identification numbers of equipment connected to the bridges, ATM addresses of the bridges, IP addresses of the bridges, and information for management of connections established in a network.
A display control means may also be included for controlling a display presented on an operator screen, which is used to instruct connection or disconnection, according to the information contained in the database.
A plurality of pieces of equipment and a plurality of bridges may transfer data according to a first communication mode. The bridges may transfer data according to a second communication mode.
Data transfer to or from the database may be performed according to the second communication mode.
The first communication mode may be a communication mode conformable to the IEEE 1394, and the second communication mode may be the ATM.
ATM communication may be performed according to the SVC mode.
According to the second aspect of the present invention, a communication control method includes a retrieving step and an output step. At the retrieving step, bridges to which two pieces of equipment out of a plurality of pieces of equipment having received an instruction of connection or disconnection are connected are retrieved from a database containing predetermined information. At the output step, a command enabling execution of the instruction is output to at least one of the bridges retrieved at the retrieving step.
According to the third aspect of the present invention, a recording medium has a program stored therein. The. program includes a retrieving step and an output step. At the retrieving step, bridges to which two pieces of equipment out of a plurality of pieces of equipment having received an instruction of connection or disconnection are connected are retrieved from a database containing predetermined information. At the output step, a command enabling execution of the instruction is output to at least one of the bridges retrieved at the retrieving step.
According to the fourth aspect of the present invention, a communication control system includes an acquiring means, a transmitting means and a setting means. The acquiring means acquires node identification numbers of a plurality of pieces of equipment. The transmitting means transmits the node identification numbers acquired by the acquiring means to other system accommodated by a network. The setting means sets a channel at which data is transmitted or received to or from equipment.
According to the fifth aspect of the present invention, a communication control method includes an acquiring step, a transmitting step, and a setting step. At the acquiring step, node identification numbers of a plurality of pieces of equipment are acquired. At the transmitting step, the node identification numbers acquired at the acquiring step are transmitted to other system accommodated by a network. At the setting step, a channel at which data is transmitted or received to or from equipment is set.
According to the sixth aspect of the present invention, a recording medium has a program stored therein. The program includes an acquiring step, a transmitting step, and a setting step. At the acquiring step, node identification numbers of a plurality of pieces of equipment are acquired. At the transmitting step, the node identification numbers acquired at the acquiring step are transmitted to other system accommodated by a network. At the setting step, a channel at which data is transmitted or received to or from equipment.
According to the seventh aspect of the present invention, a communication control system includes a requesting means, a display control means, and a reporting means. The requesting means requests acquisition of information concerning equipment accommodated by a network when a predetermined event occurs. The display control means controls a display presented on an operator screen, which is used to instruct connection or disconnection of equipment according to the information acquired in response to the request made by the requesting means. The reporting means reports information concerning equipment, of which connection or disconnection has been instructed, to other system according to the display presented on the operator screen and controlled by the display control means.
According to the eighth aspect of the present invention, a communication control method includes a requesting step, a display control step, and a reporting step. At the requesting step, acquisition of information concerning equipment accommodated by a network is requested when a predetermined event occurs. At the display control step, a display presented on an operator screen, which is used to instruct connection or disconnection of equipment, is controlled based on information acquired in response to the request made at the requesting step. At the reporting step, information concerning equipment whose connection or disconnection has been instructed is reported to other system according to the display presented on the operator screen and controlled at the display control step.
According to the ninth aspect of the present invention, a recording medium has a program stored therein. The program includes a requesting step, a display control step, and a reporting step. At the requesting step, acquisition of information concerning equipment accommodated by a network is requested when a predetermined event occurs. At the display control step, a display presented on an operator screen, which is used to instruct connection or disconnection of equipment, is controlled based on the information acquired in response to the request made at the requesting step. At the reporting step, information concerning equipment whose connection or disconnection has been instructed is reported to other system according to the display presented on the operator screen and controlled at the display control step.
According to the tenth aspect of the present invention, a communication system comprises communication control systems, a database, and a user interface. A bridge accommodated by a network includes an acquiring means, a first transmitting means, and a setting means. The acquiring means acquires node identification numbers of a plurality of pieces of equipment. The first transmitting means transmits the node identification numbers acquired by the acquiring means to a communication control system. The setting means sets a channel at which data is transmitted or received to or from equipment. The user interface includes a display control means and a second transmitting means. The display control means controls a display presented on an operator screen according to information contained in the database. The second transmitting means transmits information concerning equipment, of which connection or disconnection has been instructed, according to the display presented on the operator screen and controlled by the display control means. The communication control system includes a retrieving means, an output means, and an updating means. The retrieving means retrieves bridges, to which equipment is connected, from the database according to the information transmitted from the second transmitting means. The output means outputs a command, which enables execution of the instruction, to at least one of the bridges retrieved by the retrieving means. The updating means updates the information contained in the database according to information of new connection or disconnection sent from a bridge.
According to the fifteenth aspect of the present invention, a communication control method comprises a communication control method for a bridge, a communication control method for a user interface, and a communication control method for a communication control system. The communication control system for a bridge includes an acquiring step, a first transmitting step, and a setting step. At the acquiring step, node identification numbers of a plurality of pieces of equipment are acquired. At the first transmitting step, the node identification numbers acquired at the acquiring step are transmitted to a communication control system. At the setting step, a channel at which data is transmitted or received to or from equipment is set. The communication control method for a user interface includes a display control step and a second transmitting step. At the display control step, a display presented on an operator screen is controlled based on information contained in a database. At the second transmitting step, information concerning equipment whose connection or disconnection has been instructed is transmitted to a communication control system according to the display presented on the operator screen and controlled at the display control step. The communication control method for a communication control system includes a retrieving step, an output step, and an updating step. At the retrieving step, bridges to which equipment is connected are retrieved from the database according to the information transmitted at the second transmitting step. At the output step, a command enabling execution of the instruction is output to at least one of the bridges retrieved at the retrieving step. At the updating step, the information contained in the database is updated based on information of new connection or disconnection sent from a bridge.
According to the twelfth aspect of the present invention, a recording medium has a program stored therein. The program comprises a communication control program for a bridge, a communication control program for a user interface, and a communication control program for a communication control system. The communication control program for a bridge includes an acquiring step, a first transmitting step, and a setting step. At the acquiring step, node identification numbers of a plurality of pieces of equipment are acquired. At the first transmitting step, the node identification numbers acquired at the acquiring step are transmitted to a communication control system. At the setting step, a channel at which data is transmitted or received to or from equipment is set. The communication control program for a user interface includes a display control step and a second transmitting step. At the display control step, a display presented on an operator screen is controlled based on information contained in a database. At the second transmitting step, information concerning equipment whose connection or disconnection has been instructed is transmitted to a communication control system according to the display presented on the operator screen and controlled at the display control step. The communication control program for a communication control system includes a retrieving step, an output step, and an updating step. At the retrieving step, bridges to which equipment is connected are retrieved from the database according to the information transmitted at the second transmitting step. At the output step, a command enabling execution of the instruction is output to at least one of the bridges retrieved at the retrieval step. At the updating step, the information contained in the database is updated based on information of new connection or disconnection sent from a bridge.
In the communication control system according to the first aspect, the communication control method according to the second aspect, and the recording medium according to the third aspect, bridges to which two pieces of equipment out of the plurality of pieces of equipment having received an instruction of connection or disconnection are connected are retrieved from the database containing predetermined information. A command enabling execution of the instruction is output to at least one of the retrieved bridges.
In the communication control system according to the fourth aspect, the communication control method according to the fifth aspect, and the recording medium according to the sixth aspect, node identification numbers of the plurality of pieces of equipment are acquired, and transmitted to other system accommodated by the network. A channel at which data is transmitted or received to or from equipment is set.
In the communication control system according to the seventh aspect, the communication control method according to the eighth aspect, and the recording medium according to the ninth aspect, when a predetermined event occurs, information concerning equipment accommodated by the network is requested. The display presented on the operator screen, which is used to instruct connection or disconnection of equipment, is controlled based on the information acquired in response to the request. Information concerning equipment whose connection or disconnection has been instructed is transmitted to other system according to the display presented on the operator screen.
In the communication system according to the tenth aspect, the communication control method according to the eleventh aspect, and the recording medium according to the twelfth aspect, the bridge acquires node identification numbers of the plurality of pieces of equipment. The bridge then transmits the node identification numbers to a communication control system, and sets a channel at which data is transmitted or received to or from equipment. The user interface controls the display presented on the operator screen according to the information contained in the database. The user interface transmits information concerning equipment, of which connection or disconnected has been instructed, to a communication control system according to the display presented on the operator screen. The communication control system retrieves bridges, to which equipment is connected, from the database according to the transmitted information. The communication control system then outputs a command, which enables execution of the instruction, to at least one of the retrieved bridges, and updates the information contained in the database according to information of new connection or disconnection sent from a bridge.